i8o RUBBER AND 



serious damage to adult trees by gnawing off the bark. 

 A good deal can be done by fencing to exclude all the 

 above-named animals with the exception of monkeys, 

 but in order to be effective the fencing must be very 

 thoroughly carried out. Deer can easily clear a six-foot 

 fence, whilst barbed wire is a matter of supreme in- 

 difference to an elephant who has made up his mind 

 to proceed in a certain direction. The lower part of the 

 fence must be of wire netting if porcupines are to be 

 excluded. 



Insects. 



Under ordinary conditions a healthy Hevea tree is 

 practically immune from the attacks of boring insects, 

 owing to the presence of latex, which is found an effectual 

 check to the progress of these pests. If, on the other 

 hand, an area of bark is killed by wounding or by the 

 attacks of fungi, the latex soon dries up. Boring 

 beetles and other insects then readily obtain access, 

 and contribute materially to the damage done to the 

 tree. The insect attacks are however purely secondary, 

 and t*heir prevention is essentially bound up with that 

 of the original cause of damage, which is usually a 

 fungus disease. 



There is however one insect, prevalent in the Malay 

 Peninsula, which is able to cause considerable damage 

 to living Hevea trees without the assistance of fungi. 

 This is a species of white ant known as Termes Gestroi, 

 which is apparently able to effect an entry through the 



